The present invention relates to an electronic pace timing device, which generates physically perceptible pace timing signals at a desired presettable frequency. Such a pace timing device is widely used, to determine the rate at which various physical actions are repetitively performed. These physical actions are typified, for example, by the strides performed by a long-distance runner. During a long-distance race, it is necessary for each of the competitors to run at a pace which is best suited to his particular physical capabilities, with regard to the distance of the race. In order to determine this optimum running speed, it is necessary for the competitor to determine the relationship between running speed and the rate at which his physical capacities become exhausted. Once this has been done, the competitor can train by running at this speed, and can establish a plan for running throughout a long-distance race at that speed. A pace timing device is an extremely valuable device in the training of such a competitor, and can be used as a timing reference for measurement of running speed. Such a pace timing device generates a physically perceptible signal, e.g. an audible or visible signal, at a fixed repetition frequency. By adjusting his pace in accordance with the pace timing signals, the athlete can maintain his running speed at a desired fixed pace. In the case of a well-trained long-distance runner, the length of stride is extremely constant, so that if the number of strides per unit of time is constant, the running speed will also be constant.
In this regard, the time unit which is used to measure the running pace is an important factor. If, for example, a time unit of one hour is used, then the time required for measurement of running speed will be excessively long. If a time unit of one second is used, then there will be an insufficient number of strides during a measurement time interval, so that the accuracy of measurement will be low. For these reasons, a measurement time unit of one minute is generally adopted. During a one-minute interval, the pace of the runner will not vary by a significant amount, and the runner will perform at least one hundred strides or so during the time unit. Thus, long-distance runners generally measure their running speed in terms of the number of strides per minute. It should be noted that such a pace timing device can also be used in other spheres of physical activities, such as competitive swimmers, or rowers in a boat race. The rate of speed of a swimmer is generally measured in terms of the number of strokes per minute, while the speed of a boat competing in a boat race is usually measured as a number of oar strokes per minute. In the latter sports too, as in the case of long-distance running, it is desirable for the athletes to maintain a constant stroke repetition rate, in order to be able to produce the maximum possible physical effort over the duration of a long race.
It can thus be seen that a measurement time unit of one minute is highly suitable for a pace timing device which is applicable to various physical activities, and in particular to the training of athletic competitors. The applications of such pace timing devices are not limited to the sphere of sports, and they can also be used in some industrial activities, in order to conveniently set the rate at which some repetitively performed task is accomplished.
Hitherto, the most generally used type of pace timing device has been a metronome. However, such a mechanical type of pace timing device is inherently inaccurate, and is obviously not suited for use as a general pace timing device for competititive sports etc. Various types of electrical pace timing devices have been disclosed in the prior art. In one form of such a device, a dial provided with a graduated scale is used, whereby the repetition frequency can be adjusted by rotation of the dial to an appropriate position. As a result, the frequency of operation of an oscillator circuit (e.g. a resistance-capacitance or inductance-capacitance oscillator) is varied, to thereby change the frequency of an audible pace timing signal. Since the setting of the repetition frequency of the pace timing signal is performed in an analog manner, such pace timing devices are inherently of limited accuracy. It is possible to increase the setting accuracy by enlarging the dial, but this has the disadvantage of increasing the overall size of the pace timing device. Another disadvantage of such a prior art pace timing device is that changes in the value of the components determining the oscillator frequency will occur, as a result of temperature variations or long-term drift. Errors in the pace signal repetition frequency will therefore arise.
Another type of electrical pace timing device according to the prior art is based upon measurement of the period of an externally provided pace timing signal, memorizing this period information, and subsequently reproducing a pace timing signal having that period for its repetition frequency. The memorized period may be displayed by suitable display means, as can the pace timing signal repetition frequency. Such a method has the disadvantage however that it is necessary to provide an external source of a pace timing signal in order to produce a desired pace timing signal repetition frequency.
Another type of electrical pace timing device is based upon setting the repetition frequency of a pace timing signal as a digital numeric value, i.e. by input of digital signals. These digital signals may be input by various means such as a set of rotary switches, a ten-key switch pad (as in an electronic calculator), by repetitive actuation of a switch to produce successive input pulses, or by actuating a switch for a certain duration, during which input signal pulses are generated. The numeric value thus input, representing the pace timing signal repetition frequency can then be displayed by electro-optical display means. With such a device, the numeric value thus input is in the form of a frequency, i.e. a number of repetitions of the pace timing signal per minute. In order to produce a pace timing signal having that repetition frequency, it is necessary to convert the numeric value into a value representing the period of the desired repetition frequency. When this has been done, then a computation is carried out to determine the number of times by which the period of a standard frequency signal must be multiplied in order to produce the period of the desired pace timing signal repetition frequency. A pace timing signal having the desired repetition frequency can then be produced by frequency division of the standard frequency signal. This is the most accurate method of generating a pace timing signal of arbitrary frequency, particularly if the standard frequency signal source comprises a quartz crystal oscillator circuit. In this case, an accuracy of 0.01% or better can be attained for the repetition frequency of the pace timing signal. However, this method has the disadvantage that it is necessary to provide a quite extensive amount of circuitry in order to perform the calculations whereby a numeric value representing a pace timing signal repetition frequency is converted into period information. If the pace timing signal generating function is to be added to an electronic calculator as an added feature, there is no essential disadvantage to adopting the latter method. However, in the case of a device which is only to provide a pace timing function, or an electronic timepiece which is to have a pace timing function added to it, it is undesirable to provide circuitry simply to perform digital calculations, since various disadvantages such as increased cost and circuit complexity will result.
As described hereinafter, the present invention provides a pace timing device which has the advantages of accuracy and ease of input of a desired pace timing signal repetition frequency, provided by the latter-mentioned prior art pace timing device, but which does not require digital calculations to be performed upon an input numeric value representing the desired repetition frequency in order to produce a pace timing signal having that frequency. A pace timing device according to the present invention can therefore have a simple circuit configuration, enabling the manufacturing cost and power consumption of the device to be reduced by comparison with prior art electrical pace timing devices of digital type.